It is difficult to fully understand a lumbar spinal fusion without briefly discussing the normal anatomy of the spine. The vertebral or spinal column consists of 33 bones called vertebrae. Each are that stacked on top each other to for them spine. The spine, which extends from the base of skull to the pelvis, has four regions: the cervical spine, thoracic spine, lumbar spine and the sacrum. Between each vertebra are the flat and circular plates of cartilage called the interverbral discs. Intervetebral discs maintain the integrity and continuity of the spine by holding one vertebra to the next. It acts as an effective cushion that absorbs shock and pressure placed by the everyday movements of the back. This disc also makes bending and head rotations possible.
The lumbar spine makes up the lower back, extending from the lumbar curve down to the sacrum. Among the four regions of the spine, the lumbar region endures the greatest stress. Carrying the entire body weight, this region is supported by the five thickest and sturdiest of all vertebrae of the spinal column. It has also been determined that the intervertebral discs between two adjacent lumbar vertebrae are the thickest. Attaching to the lumbar vertebra are some of the largest stabilizing muscles of the lower back, which include the lumbar erector spinae, psoas and quadratus lumborum. Because the greatest amount of work and stress are placed against this region of the spine, the lumbar spine is most susceptible to injuries and structural alterations.
How Common is Spinal Fusion Surgery?
It is estimated that more than 300,000 spinal fusion surgeries are performed in the United States each year (Pakzaban, 2009). A large number
of these operations are performed to relieve degenerative diseases in the spine. According to the American Academy of Orthopaedic Surgeons (2009), there were more than 325,000 spinal fusions performed in 2003. Of this number, 162,000 fusions involved the lumbar spine. From 1996 to 2001, the number of lumbar fusions increased to as much as 113%. The percentage of lumbar fusion rapidly increased among patients aged 60 years and above.
Bederman and colleagues (2008) determined that between 1995 and 2001, 6128 patients over 50 years underwent spinal surgery for degenerative lumbar disease in Ontario, Canada. Of this population, 1928 patients underwent lumbar fusion, whereas 4200 patients had spinal decompression. Although the number of decompression surgeries was greater, researchers found that an increasing proportion of fusions over decompressions occurred during this time period. Overall, the rate of lumbar fusion reoperation was found at 10.4% within 2 years after the procedure. It was determined that the rates of lumbar fusion have been increasing in Ontario; however, the rates were less when compared with those documented in the United States.
The above was part 2 of a spinal fusion and exercise series.